This invention relates to a horizontal fish detection sonar which detects the depth of water, a school of fish, etc. at any determined distance in the direction of the travelling sound wave.
One of the vertical fish detection sonars widely used in the prior art fish detection sonar emits ultrasonic waves from the bottom of the ship toward the bottom of the sea and receives reflected waves from the bottom of the sea or a swimming school so as to measure the depth of water at the present location or the distance from the ship to a school of fish.
One of the horizontal fish detection sonar widely used in the prior art fish detection sonar emits an ultrasonic wave in a horizontal direction in the front of the ship and receives reflected waves from a target, a school of fish, or obstructions so as to measure the distance from the ship to the target, the school of fish, or the obstructions.
However, the prior art fish detection sonars of the type described have a distinct defect that it is impossible to measure the depth of water, a school of fish, or obstructions at any determined distance in the front of the ship.